Hanako Oku (奥 華子 Oku Hanako?, born March 20, 1978 in Funabashi, Chiba, Japan) is a pop singer famous in her native Japan for her piano ballads. She rose to fame after performing the end-title track for the Madhouse film The Girl Who Leapt Through Time in 2006. She was signed to a major record label the preceding year.
Oku's musical training began at age 5 with piano lessons, but by age 9 she was also learning the trumpet and was a member of her school's brass band.
In 2004, Oku began to perform on the streets of Tokyo, mainly in Shibuya ward, but once sold 402 CDs in four hours outside Kashiwa railway station. Later that same year she released her first mainstream single Fireworks and performed her debut one-woman show to an audience of 135. Approached by Chiba TV, she made an appearance on the show Chiba Fighting Spirit.
Over the next year she toured western Japan and self produced two more CD singles before releasing an album in April 2005. Soon afterwards she was signed up by record company Pony Canyon.
In April 2006, the animated film The Girl Who Leapt Through Time was released, with the theme songs Garnet and Kawaranai Mono sung by Oku. Come spring 2007, Oku performed to a sell-out crowd at Shibuya C.C. Lemon Hall, and with the release of her album Time Note, she once again performed sold-out concerts there over three nights in July 2007. Oku still occasionally busks in Tokyo railway stations, drawing a crowd, and selling her CDs there.
Since June 2005, Hanako Oku has hosted her KameKameHouse radio show on bayfm78 every Sunday night from 22:30 to 23:00. At the end of 2009, the show was renamed Lagan de Talk!. In 2010, Oku began hosting a new radio show E-Tracks Selection once a fortnight on FM OSAKA. Starting January 12, the show airs from 21:00 to 21:30.